Goodwill and Other Intangibles Intangible Lease Assets and Liabilities, Projected Amortization Expense and Adjustments to Rental Income (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Below-market lease liabilities, amortization income, 2015	$ 28,881
Below-market lease liabilities, amortization income, 2016	22,752
Below-market lease liabilities, amortization income, 2017	22,608
Below-market lease liabilities, amortization income, 2018	22,276
Below-market lease liabilities, amortization income, 2019	21,532
Leases, Acquired-in-Place [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization expense, 2015	195,682
Amortization expense, 2016	182,450
Amortization expense, 2017	165,900
Amortization expense, 2018	151,892
Amortization expense, 2019	142,032
Leasing Commissions [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization expense, 2015	445
Amortization expense, 2016	472
Amortization expense, 2017	459
Amortization expense, 2018	351
Amortization expense, 2019	327
Above Market Leases [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization expense, 2015	27,129
Amortization expense, 2016	26,978
Amortization expense, 2017	26,598
Amortization expense, 2018	26,016
Amortization expense, 2019	$ 24,033